With a continuous development of the semiconductor technology, the size of integrated circuit element device has been less than 100 nm. When high energy charged ions from the aerospace or the ground pass through the integrated circuit element device, a large number of electron hole pairs deposited in the track are collected by sensitive nodes (i.e. reversed biased pn junctions) of the integrated circuit element device, which causes an improper variation of logic states of the element device or damage to the element device. For conventional integrated circuit element devices, spaces between the element devices are large. An electron hole pair along the track of charged ions generally can only be collected by one sensitive node of an element device. However, in order to increase the integration density of the integrated circuit, spaces between the element devices are continuously reduced, the electron hole pair along the track of charged ions diffuse into other element devices before recombination and will be collected in the vicinity of other sensitive nodes, and this phenomenon is referred as a charge sharing effect. The charge sharing effect may cause multiple nodes in the integrated circuit switch simultaneously, increase a switching section, and reduce an energy threshold required for the switching. Also, the charge sharing effect causes a failure of a radiation hardening technology at a device level and a circuit level such as the guard-rings.
As shown in FIG. 1, when heavy ions enter into a conventional CMOS device of small size, due to the influence of heavy ions, an electron hole pair 04 generated near the heavy ion incidence track 05 diffuses from an incidence main device 02 to a device 03 near the incidence main device 02, an isolation region 01 of the conventional device can not suppress the charge sharing effect during the heavy ion radiation.